Interlocking concrete construction



H. R. CARPER INTERLOCKING CONCRETE CONSTRUCTION Nov. 13, 1962 2 Sheets-Sheet 1 Filed June 21, 1954 INVEN TOR. 14m, R (YE/ ER, BY f Nov. 13, 1962 H. R. CARPER INTERLOCKING CONCRETE CONSTRUCTION 2 Sheets-Sheet 2 Filed June 21, 1954 INVENTOR. 77201; 072, 52;

TTOQIVE Y5.

United States Patent Ofifice 3,063,202 Patented Nov. 13, 1962 INTERLQCKING CONCRETE CONSTRUCTION Harold R. Carper, Indianapolis, Ind., assignor of thirtyfive and five-ninths percent to Carl F. Spickelmier,

thirty-two and two-ninths percent to Edith S. Greer,

and thirty-two and two-ninths percent to Betty S.

Spicklemier, all of Indianapolis, Ind.

Filed June 21, 1954, Ser. No. 438,033 3 Claims. (Cl. 50-370) This invention relates to that type of building construction in which slabs serving as roofs or floors are made up of prefabricated reinforced concrete planks or beams held in side-by-side relationship. One of the difficulties encountered in the production of such slabs arises from individual differences among the beams as a result of inevitable variations in manufacture. The beams may not all have the same initial camber or may not sag to the same extent when put in place. Such variations create offsets which are objectionable in ceilings where the lower face of the slab is exposed. This difficulty is perhaps most pronounced in the case of beams made up of individual blocks secured together by continuous reinforcing members grouted in place. Beams of this kind are more fully set forth and described in my prior Patent No. 2,949,705, granted August 23, 1960.

Variations among the individual beams or planks which are to form a floor or roof slab can be reduced by careful control of manufacturing operations; but since only minor variations among the several beams may result in unsightly vertical offsetting creating an undesirable appearance, it has been proposed to provide the beams with interfitting provisions which will tend to maintain adjacent beams at the same elevation throughout their longitudinal extent. However, such interfitting provisions as have heretofore been used have not proven completely satisfactory.

It is therefore an object of this invention to provide beams which are to be used in the construction of a floor or ceiling slab with interfitting provisions of improved type which will accurately maintain adjacent beams at the same elevation throughout their extent. A further object of the invention is to provide an improved means for distributing between the beams the load imposed on the finished slab. Still another object of the innvention is to produce the desired mutual alignment of beams and the distribution of load among them without increasing the cost of manufacture or complicating the assembly of the slab.

In carrying out the invention in its preferred form, I provide one side face of each beam with a longitudinally extending tongue and the other with a groove adapted to receive the tongue of the adjacent beam. The tongues and grooves have complementarily tapered top and bottom surfaces; and below the tongue and grooves the side faces of the beams are provided with shoulders which, by interengagement, prevent the tongue from completely seating in the groove which receives it. Above the mating tongues and grooves the blocks are so shaped as to leave a gap between them when the shoulders just mentioned are in engagement with each other. The upper longitudinal edges of the beams are provided with undercut rabbet grooves defining a space into which grouting may be poured after the beams have been assembled to form a slab.

The accompanying drawings illustrate the invention:

FIG. 1 is a fragmental plan view of a reinforced con crete slab, which might be either a roof or a floor slab;

FIG. 2 is a side elevation of the slab shown in FIG. 1;

FIG. 3 is a fragmental perspective view showing an end of the slab on an enlarged scale; and

FIG. 4 is an isometric view illustrating an individual block which may be used in forming the beams which are assembled into the finished slab.

The beams illustrated in the drawings are formed of individual concrete blocks 10 each having a central void 11 and openings 12 extending horizontally through it from one side face to the other. As more fully brought out in my co-pending application above referred to, a plurality of blocks 10, having accurately finished side faces, are arranged in a row and clamped together, and thereafter reinforcing rods 13 extending for the length of the beam are positioned in the holes 12 and the holes 12 are filled with grouting 14. Longitudinal clamping effort is maintained on the beam until the grouting has set, whereupon the clamping effort may be relieved and the beam becomes ready for installation in a slab. In use, a plurality of beams so formed are arranged in side-by-side relation and supported at their ends as on walls 15.

Because of variations in manufacture, the several beams which enter into a slab may not all have the same camber or may not all sag to the same extent under dead load when put in place. Accordingly, it is desirable to provide adjacent beams with interlocking provisions serving to maintain them flush with each other at their upper and lower surfaces. This invention is particularly directed to interlocking provisions of improved type for accomplishing that purpose.

Intermediate the vertical extent of each block 10, the

end faces of the block are provided respectively with a,

tongue 17 and a groove 18 having complementarily tapered upper and lower surfaces. Below the tongue 17 the end face of the block lies vertically to provide a shoulder 20, while below the .groove 18, the end of the block likewise lies vertically to form a shoulder 21. As will be clear from FIG. 3, the tongues and grooves are so proportioned and the shoulders 20, 21 so located that engagement of the shoulders prevents the tongues 17 of one beam from completely seating in the groove 18 of the adjacent beam. The shoulders 20 and 21' have the same height, so that with the lower faces of a mating tongue and groove engaged and with the shoulders 20 and 21 also engaged the lower surfaces of adjacent beams will be substantially flush with each other.

The upper and lower edges of each block are provided with undercut rabbet grooves 23 the bottoms of which are spaced above the adjacent tongues 17 or grooves 18 to leave generally vertical surfaces 24 and 25. The horizontal distance between the surface 24 and 25 is less than that between the shoulders 20 and 21 with the result that between adjacent beams there is a space or gap extending from the upper faces of the beams to the lower surface of the groove 18. When the slab is assembled, this gap is filled with grouting 27.

It has been my experience in manufacturing beams by the method above described and more fully set forth in my co-pending application that the majority of the beams will all have substantially the same camber and will all tend to sag substantially to the same extent under dead load when installed and supported at their ends. The greatest departure from the substantially constant camber or sagging tendency occur in the direction of deficient camber or insufficient rigidity. When a slab is assembled, by laying a plurality of individual beams in side-by-side relationship and then forcing them together by a clamping effort applied laterally of the beams to cause the tongues 17 to enter the grooves 18, the lower face of the tongue 17 of a sagging beam will be engaged by the sloping lower face of the associated groove 18; and as the beams move together the sagging beam will be elevated by virtue of the inclination of the interengaging faces. Because of the clearance between each tongue and its associated groove, the entrance of the tongue into the groove will be limited only by engagement of the shoulders 20 and 21; and as such shoulders have the same width, the lower surfaces of adjacent beams will be brought into a flush relationship. The inclination of the lower surfaces of the tongues and grooves is at an angle whose tangent is less than that of the coefficient of friction between the surfaces of the concrete blocks. Therefore, Once adjacent beams have been forced together to an extent sufiicient to cause interengagement of the shoulders 20 and 21, it is not necessary to maintain the cramping efiort.

After the beams have all been forced together to the limit provided by engagement of the shoulders 29 and 21, grouting 27 is poured into the rabbet grooves 23, such grouting running down below such grooves into the spaces between the faces 24 and 25 and between the upper and side faces of the tongues 17 and grooves 18, as indicated in FIG. 3. Such grouting serves to key adjacent beams together, the undercut character of the rabbet grooves 23 permitting the transfer of substantial vertical shearing stresses from beam to beam in either direction and favoring the distribution of loads among the several beams of the slab.

FIGS. 3 and 4 illustrate, approximately to scale, the portions of a block for use in producing slabs of six-inch thickness. The tongue 17, at its base, may have a vertical dimension of one and one-half inches and may project three-quarters of an inch beyond the shoulder 20, its lower face rising three-sixteenths of an inch in that distance of projection. The ratio of rise to projection is therefore 0.25, which is approximately the tangent of 15 and substantially less than the coeificient of friction between the engaging concrete surfaces of the tongue and groove. The

'groove 18 is preferably about one-eighth inch wider vertically and about one-eighth inch deeper than the tongue. It will be understood that these specific dimensions are set forth by way of example rather than as limitations, that I do not limit myself to the particular forms of blocks and beams illustrated and described, and that the scope of the invention is to be measured by the appended claims.

I claim as my invention:

1. In building construction, a plurality of similar beams arranged in substantially coplanar, side-by-side relation to form a horizontal slab, each of said beams being provided on one side and intermediate its height with a longitudinal tongue and on the opposite side and also intermediate its height with a longitudinal groove receiving the tongue of an adjacent beam, said groove having a downwardly and outwardly inclined lower face, said tongue having a complementarily inclined lower face resting on the lower face of the groove in an adjacent beam, said beams below the tongues and grooves and contiguous thereto having shoulders which engage each other to limit entrance of the tongues into the grooves, each of said tongues projecting outwardly beyond its associated shoulder for a distance less than the depth of the groove which receives it to provide a gap between the tongue and the base of the groove, each of the tongues being narrower than the groove which receives it to provide a second gap between upper faces of the tongue and groove, said second gap communicating with said first gap, the adjacent sides of adjacent beams above the tongue being spaced apart to provide a third gap extending to the upper face of the slab and communicating with the second gap, and grouting filling said gaps.

2. The invention set forth in claim 1 with the addition that each of said beams is provided at its upper long tudinal edges with rabbet grooves, adjacent rabbet grooves of adjacent beams defining a longitudinally extending channel forming the upper portion of said third gap and filled with grouting.

3. The invention set forth in claim 1 with the addition that each of said beams comprises a series of discrete blocks having abutting faces extending transversely of the beam and provided with aligned passages for the reception of a reinforcing member, a reinforcing member extending longitudinally of the beam through said passages, and grouting in said voids to hold said reinforcing members in place.

References Cited in the file of this patent UNITED STATES PATENTS 1,028,578 Lund June 4, 1912 1,214,442 Edlin Jan. 30, 1917 2,162,872 White June 20, 1939 2,234,114 Gifford Mar. 4, 1941 2,413,990 Muntz Jan. 7, 1947 2,644,497 Wilmer et al July 7, 1953 FOREIGN PATENTS 68,760 Switzerland Apr. 16, 1915 628,717 France July 5, 1927 309,083 Great Britain May 15, 1930 574,496 Great Britain Jan. 8, 1946 142,311 Sweden July 16, 1953 1,064,471 France Dec. 23, 1953 

